Field of the Invention
The present invention relates to a touch panel to minimize a signal distortion and a display apparatus including the same, and more particularly, to a touch panel to minimize a signal distortion due to an electrical effect between each of the TFT signal lines of a TFT substrate and each of the touch signal lines of a touch panel by patterning the TFT signal lines and the touch signal lines in an optimal structure in which the TFT signal lines and the touch signal lines are not vertically opposite to each other in a state in which the touch panel is mounted on a display panel including the TFT substrate, and a display apparatus including the same.
Discussion of the Background
FIG. 1 illustrates a configuration of a general display apparatus. Referring to FIG. 1, in a general display apparatus 1, a touch panel 10 detecting a touch by a touch input means 2 is mounted on a display panel 20 outputting an image.
Describing in more detail, the display panel 20 has a structure in which a TFT substrate 30 is disposed at a lower part of the display panel 20 and a liquid crystal layer 23 is formed by sealing a liquid crystal between a color filter 21 disposed at an upper part of the display panel and the TFT substrate 30. To seal the liquid crystal, outer portions of the TFT substrate 30 and the color filter 21 are bonded to each other by a sealant 25. Further, although not illustrated, polarizing plates are not only attached to the upper and lower parts of the display panel 20, but back light units are also installed at the upper and lower parts of the display panel 20.
Further, as illustrated, the touch panel 10 is disposed on the display panel 20. In the touch panel 10, linear touch pads 11 are patterned on the upper surface of the touch substrate 16 and a passivation layer 15 disposed over the touch pads to cover the touch pads 11 from the outside.
The touch panel 10 is bonded to edge parts of the display panel 20 by an adhesive member 40 such as a double adhesive tape (DAT). In this case, an air gap 24 is formed between the adhesive member 40 and the touch panel 20.
Meanwhile, FIG. 2 illustrates a configuration of a general touch panel 10. Referring to FIG. 2, in the general touch panel 10, the plurality of touch pads 11 which senses touches by the touch input means 2 to output touch signals and touch signal lines 12 applying the touch signals of each of the touch pads 11 to a touch drive IC 13 are patterned on the touch substrate 16.
With the disposition structure of the touch pads 11 and the touch signal lines 12 which are patterned, the touch panel 10 is divided into a touch active area TAA (portion shown by a dotted line) in which the touch pads are disposed to be able to sense the touch by the touch input means 2 and a touch black-matrix area TBA (portion shown by a shade) in which the touch pads 11 are not disposed not to be able to sense the touch.
In this configuration, the touch pads 11 are patterned on the touch substrate 16 in a form in which the plurality of touch pads 11 are aligned within the TAA at a predetermined distance so as to provide a uniform touch input and the touch signal lines 12 are formed on the touch substrate 160 while extending toward a direction in which the touch drive IC 13 is disposed to electrically interconnect between each touch pad 11 and the touch drive IC 13.
FIG. 2 illustrates that as the touch drive IC 13 is disposed at the lower part based on a position where each touch pad 11 is disposed, each touch signal line 12 is drawn out from sides of the touch pads 11 and extends downward while being bent. However, when the touch drive IC 13 is disposed at the side or the upper part of the touch pad 11, each touch signal line 12 is bent laterally or upward to extend toward the touch drive IC.
Meanwhile, FIG. 3 illustrates a detailed configuration of a unit pixel which is formed the general TFT substrate 30 and FIG. 4 schematically illustrates a configuration of the TFT substrate 30.
Referring to FIG. 3, the TFT substrate 30 is vertically and horizontally provided with gate signal lines 31a and source signal lines 31b. 
A gate electrode 38 of a TFT 36 is connected to the gate signal line 31a to be applied with a scanning signal and a source electrode 34 and a drain electrode thereof are each connected to the source signal line 31b and a pixel electrode line 39. Further, a substrate 33 of the TFT 36 forms a channel between the source electrode 34 and the drain electrode 35 to apply an image signal to the liquid crystal layer 23. As illustrated, a common electrode line 37 is formed within a pixel, in parallel with the pixel electrode line 39.
Therefore, when the TFT 36 is operated to apply the image signal to the pixel electrode line 39, a horizontal electric field is substantially generated between the common electrode line 37 and the pixel electrode line 39, and as a result a predetermined screen is displayed while liquid crystal molecules of the liquid crystal layer 23 moves on a plane.
Further, as illustrated in FIG. 4, in the TFT substrate 30, the TFT signal line 31 including the gate signal lines 31a and the source signal lines 31b is disposed on the substrate 33 and the entire area is divided into a display black-matrix area DBA (portion shown by a shade) without a pixel and a display active area DAA (portion inside a shade) in which the pixel is disposed to display an image. Further, one side of the substrate 33 is provided with a display drive IC 32 which generates a gate signal and a source signal for driving each pixel to display an image on the display panel 20.
In addition, the gate signal lines 31a and the source signal lines 31b which extend in a direction in which the display drive IC 122 is disposed are each patterned within the DBA to apply the gate signal or the source signal output from the display drive IC 32 to the TFT 36, thereby applying the gate signal or the source signal, which is sourced from the display drive IC 32, to each pixel.
Further, as illustrated in FIGS. 1 and 5, the touch panel 10 is disposed on the TFT substrate 30 in a form in which the touch panel 10 and the TFT substrate may vertically overlap with each other, and therefore each area of the TBA and TAA of the touch panel 10 and each area of the DBA and the DAA of the TFT substrate 30 may overlap with each other.
Here, FIG. 6 illustrates a state in which some of the touch pads 11a, 11b, and 11c and some of the touch signal lines 12a, 12b, and 12c are disposed to overlap with the DBA of the TFT substrate 30 while the existing touch panel 10 is seated on the TFT substrate 30.
Referring to FIGS. 1 and 6, the touch pads 11 and the touch signal lines 12 of the touch panel 11 are formed on a TFT upper surface adhesive. If it is assumed that the TFT upper surface adhesive is the color filter 21 of a glass material and a vertical thickness of the color filter 21 is 0.5 mm, the plurality of gate signal lines 31a and each touch pad 11 which are illustrated in FIG. 6 are vertically spaced apart from each other by 0.5 mm and are more spaced apart from each other by a thickness of the adhesive member 40.
In this case, a touch pad 11a illustrated at the left of FIG. 5 is disposed to be vertically opposite to the gate signal line 31a which is disposed in the DBA present at the left of the TFT substrate 30. In this case, when a pitch of the gate signal line 31a is 20 μm and the touch pad 11a has a thickness of 200 μm, the corresponding touch pad 11a is vertically opposite to 10 gate signal lines 31a within the DBA.
Further, the touch pad 11b and the touch signal line 12a which are illustrated at the right of FIG. 6 are disposed in the DBA in which the gate signal line 31a is disposed. If it is assumed that a width of the touch signal line 12a is 100 μm, one touch signal line 12a is vertically opposite to 5 gate signal lines 31b. In addition, the touch pad 11c and the touch signal line 12b which are illustrated at the lower part of FIG. 6 are vertically opposite to the source signal line 31b while being disposed in the DBA in which the source signal line 31b is disposed.
As such, when each of the touch pads 11a, 11b, and 11c, and the touch signal lines 12a and 12b of the touch panel 10 are vertically opposite to TFT signal lines 121 such as the gate signal line 31a and the source signal line 31b while being disposed in the DBA of the TFT substrate 120 in which the gate signal line 31a and the source signal line 31b are disposed, the gate signal line 31a and the source signal line 31b sequentially turns on/off the gate electrode and the source electrode by a time sharing method, and therefore as illustrated in FIG. 7, an electrical effect of a voltage applied depending on the turn on/off driving of the TFT signal line 31 including the gate signal line 31a and the source signal line 31b is applied to the touch pads 11a, 11b, and 11c and the touch signal lines 12a and 12b, such that the sensed or transferred touch signals may be coupled to be distorted or may be mixed with a noise signal.